Conjoint production of ditertiary butyl peroxide and tertiary butyl alcohol from tertiary butyl hydroperoxide

Abstract: A method for conjointly preparing tertiary butyl alcohol and ditertiary butyl peroxide wherein a solution of a tertiary butyl hydroperoxide feedstock in tertiary butyl alcohol is charged to a hydroperoxide decomposition reaction zone containing a catalytically effective amount of a hydroperoxide decomposition catalyst consisting essentially of palladium supported on pelleted carbon, and is brought into contact with the catalyst in liquid phase under hydroperoxide decomposition reaction conditions to convert the tertiary butyl hydroperoxide to decomposition products, principally tertiary butyl alcohol and ditertiary butyl peroxide.

Description: This invention relates to the conjoint production of tertiary butyl alcohol and ditertiary butyl peroxide from tertiary butyl hydroperoxide. More particularly, the invention relates to a continuous catalytic method for the conjoint production of tertiary butyl alcohol and ditertiary butyl peroxide from a solution of tertiary butyl hydroperoxide in tertiary butyl alcohol. Still more particularly, this invention relates to a continuous method for the conjoint production of tertiary butyl alcohol and ditertiary butyl peroxide by bringing a tertiary butyl alcohol solution of tertiary butyl hydroperoxide into contact with a pelleted carbon catalyst having palladium deposited thereon. It is known to react isobutane with oxygen, either thermally or catalytically, to form a peroxidation reaction product wherein the principal peroxide that is formed is tertiary butyl hydroperoxide. It is also known to thermally or catalytically decompose the tertiary butyl hydroperoxide to form tertiary butyl alcohol. It is also known, as pointed out in US-A-4,810,809 and 4,900,850 that ditertiary butyl peroxide is a minor constituent of the reaction product. Ditertiary butyl peroxide is a valuable commercial product used, for example, as a high temperature free radical initiator in chemical reactions. These two patents disclose methods that can be used to recover purified ditertiary butyl peroxide from a reaction product formed by the thermal or catalytic decomposition of tertiary butyl hydroperoxide. Sanderson et al. disclose the use of a variety of catalysts for the decomposition of tertiary butyl hydroperoxide in a series of U. S. patents, including a catalyst composed of unsupported nickel, copper, chromia and iron (U. S. Patent No. 4,704,482), a catalyst composed of iron, copper, chromia and cobalt (U. S. Patent No. 4,705,903), a catalyst composed of a base treated hydrogenation catalyst from groups VIA or VIII of the Periodic Table (U. S. Patent No. 4,742,179), a catalyst consisting essentially of nickel, copper, chromium and barium (U. S. Patent No. 4,873,380), a catalyst composed of a metal phthalocyanine promoted with a rhenium compound (U. S. Patent No. 4,910,349), a catalyst composed of a base promoted metal phthalocyanine compound (U. S. Patent No. 4,912,269), a catalyst composed of a soluble ruthenium compound promoted with a bidentate ligand (U. S. Patent No. 4,912,033), a catalyst composed of a metal porphine such as iron (III) or manganese (III) promoted with an alkyl thiol or an amine, a catalyst composed of an imidazole promoted metal phthalocyanine compound (U. S. Patent No. 4,912,266), (U. S. Patent No. 4,922,034), a catalyst composed of a metal phthalocyanine promoted with a thiol and a free radical inhibitor (U. S. Patent No. 4,922,035), a catalyst composed of a borate promoted metal phthalocyanine (U. S. Patent No. 4,922,036), or a catalyst composed of a soluble ruthenium compound and an iron compound such as an acetate, a borate, a bromide, a chloride, a 1,3-propanedionate, a 2-ethyl-hexanoate, an iodide, a nitrate, a 2,4-pentanedionate, a perchlorate or a sulfate (U. S. Patent No. 5,025,113). As stated, when isobutane is reacted with molecular oxygen, the principal products of the reaction are tertiary butyl alcohol and tertiary butyl hydroperoxide. However, minor amounts of other oxygen-containing contaminants are also formed. A minor amount of water will be formed, which will normally amount to 0.5 to 1 wt.% of the reactor effluent. The amount of byproduct water that is produced is a function of the severity of the reaction conditions employed and will tend to increase as the severity of the reaction conditions is increased. As indicated, tertiary butyl hydroperoxide is useful as a raw material for the manufacture of tertiary butyl alcohol and ditertiary butyl peroxide. It has been discovered in accordance with the present invention that tertiary butyl alcohol and an enhanced amount of ditertiary butyl peroxide are formed when a solution of tertiary butyl hydroperoxide in tertiary butyl alcohol is brought into contact with a catalytically effective amount of a catalyst consisting essentially of pelleted carbon having palladium deposited thereon. Tertiary butyl alcohol and ditertiary butyl peroxide can be recovered from the products of the reaction. The starting materials for the process of the present invention are a tertiary butyl hydroperoxide feedstock and a carbon supported palladium catalyst. The Tertiary Butyl Hydroperoxide Feedstock The tertiary butyl hydroperoxide charge stock may comprise an isobutane oxidation product wherein the tertiary butyl hydroperoxide is dissolved in a mixture of isobutane and tertiary butyl alcohol or may comprise an isobutane oxidation product enriched by the addition of tertiary butyl alcohol, such that the solution of tertiary butyl alcohol in the mixture of isobutane with tertiary butyl alcohol contains from 5 to 30 wt.% of tertiary butyl hydroperoxide. Alternatively, the isobutane reaction product may be charged to a distillation zone where unreacted isobutane is removed as a distillate fraction for recycle to thereby provide a solution of tertiary butyl hydroperoxide in tertiary butyl alcohol containing 5 to 30 wt.% of tertiary butyl hydroperoxide. The Catalyst The catalyst to be used in accordance with the present invention consists essentially of carbon-supported palladium, such as pelleted carbon having from 0.1 to 1 wt.% of palladium deposited thereon. Catalytic Decomposition of Tertiary Butyl Hydroperoxide The process of the present invention may be conducted batchwise in kettles or by continuously passing the reactants through a tubular reactor. The catalytic decomposition of the tertiary butyl hydroperoxide is preferably conducted at a temperature within the range of 20° to 160°C, preferably 60° to 120°C, and more preferably at a temperature within the range of 80° to 100°C. The reaction is preferably conducted at a pressure sufficient to keep the reactants and the reaction products in liquid phase. A pressure of about 0.1 to 7 MPa (0 to 1,000 psig) may be used, if desired. Flow rates of the charge solution to the reaction zone should be adjusted in order to provide an appropriate contact time within the reactor. In a batch process, the holding time may suitably be from 0.5 to 10 hours, and more preferably 1 to 3 hours. In accordance with a preferred embodiment of the present invention, isobutane is reacted with oxygen in an oxidation zone under oxidation reaction conditions including a temperature of 135 to 155°C., a pressure of 2.1 to 5.6 MPa (300 to 800 psig), and a holding time of 2 to 6 hours to provide an initial oxidation reaction product comprising unreacted isobutane, tertiary butyl hydroperoxide, tertiary butyl alcohol, and oxygen-containing by-products. The initial oxidation reaction product is then used as the tertiary butyl hydroperoxide charge stock of the present invention. If the concentration of tertiary butyl hydroperoxide in the tertiary butyl hydroperoxide charge stock is more than 30 wt.% of the initial oxidation reaction product, the initial oxidation reaction product can be diluted with an amount of tertiary butyl alcohol sufficient to lower the concentration of the tertiary butyl hydroperoxide to a desired percentage, to provide, for example, a tertiary butyl hydroperoxide charge stock containing from 15 to 25 wt.% of tertiary butyl hydroperoxide. Alternatively, the initial oxidation reaction product may be fractionated in any appropriate manner (e.g., by distillation in a distillation zone) to remove the isobutane therefrom for recycle and to provide a solution of tertiary butyl hydroperoxide and tertiary butyl alcohol which will normally contain from 5 to 30 wt.% of tertiary butyl hydroperoxide. The solution of tertiary butyl hydroperoxide in tertiary butyl alcohol is then charged to a catalytic hydroperoxide decomposition zone where it is brought into contact with an a carbon-supported palladium catalyst to conjointly convert the tertiary butyl hydroperoxide to tertiary butyl alcohol and ditertiary butyl peroxide with high yields and selectivities. When the process of the present invention is practiced in a continuous manner by continuously charging the tertiary butyl hydroperoxide charge stock to a reactor containing a fixed bed of pelleted hydroperoxide decomposition catalyst, the space velocity is suitably in the range of 0.5 to 3 volumes of tertiary butyl hydroperoxide charge stock per volume of catalyst per hour. Preferably, the space velocity is within the range of 1 to 2 volumes of tertiary butyl hydroperoxide charge stock per volume of catalyst per hour. The reaction product from the tertiary butyl hydroperoxide decomposition step may then be fractionated in any suitable manner, such as by distillation to recover the tertiary butyl alcohol. EXAMPLES The invention will be further illustrated by the following non-limiting examples. Procedure A 20 wt.% solution of tertiary butyl hydroperoxide in tertiary butyl alcohol was used as the reactor feed. Analysis of the reactor effluent was by Gas Chromatography. Details are given in the following tables. Example 1 Reactor The reactor was a stainless steel tube (13mm x 736mm) which was electrically heated. Liquid feed was pumped into the bottom of the reactor. Pressure regulation was with a Skinner Uni-Flow® valve and a Foxboro® controller. The liquid feed was pumped with a Ruska® dual drive pump. In this example, the catalyst consisted essentially of palladium supported on pelleted carbon. A palladium on carbon catalyst gave conversion of TBHP similar to the palladium on alumina catalysts, but the selectivity to DTBP was much higher--especially at lower temperatures. For example, at 80°C (0.5 space velocity), a 79.1% conversion of TBHP was observed with a selectivity to TBA on 73.5% and a selectivity to DTBP of 21.5%. On the other hand, under the same conditions, but with a Pd/Pt on alumina catalyst, at 74.2% conversion of TBHP was observed with selectivity to TBA of 84.1% and DTBP of 5.0%. CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL AND DITERTIARY BUTYL PEROXIDE RUN A 1 2 3 4 Catalyst .8% Pd on Carbon Catalyst (cc) 100 100 100 100 Pressure (MPa) 2.1 2.1 2.1 2.1 Feed Rate (cc/Hr.) 50 50 50 50 Temperature (°C) 60 80 100 120 Time on Stream (Hr) 4 4 4 4 Space Vel. (cc/cc) 0.5 0.5 0.5 0.5 TBHP Conversion (mol.%) 79.1 74.2 94.3 99.8 Selectivity IC4= (mol.%) 0.1 0.2 0.9 23.7 Sel. Acetone (mol.%) 5.0 7.1 10.0 15.3 Sel. Methanol (mol.%) 0.9 2.3 3.3 3.4 Sel. TBA (mol.%) 73.5 75.8 79.6 78.4 Sel. DTBP (mol.%) 21.5 17.1 10.4 6.4 Composition, wt% IC4= 0.000 0.006 0.018 0.110 3.012 MEOH/MF 0.005 0.058 0.130 0.234 0.254 Acetone 0.013 0.534 0.711 1.265 2.027 TBA 78.494 90.807 89.375 92.484 90.374 DTBP 0.049 2.879 2.157 1.674 1.108 TBHP 20.512 4.293 5.289 1.169 0.041 CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL AND DITERTIARY BUTYL PEROXIDE RUN A 5 6 7 8 Catalyst .8% Pd on Carbon Catalyst (cc) 100 100 100 100 Pressure (MPa) 2.1 2.1 2.1 2.1 Feed Rate (cc/Hr.) 100 100 100 100 Temperature (°C) 60 80 100 120 Time on Stream (Hr) 4 4 4 4 Space Vel. (cc/cc) 1.0 1.0 1.0 1.0 TBHP Conversion (mol.%) 11.7 53.6 79.2 98.8 Selectivity IC4= (mol.%) 0.7 0.6 1.3 14.3 Sel. Acetone (mol.%) 8.0 8.0 11.2 21.0 Sel. Methanol (mol.%) 2.0 2.0 4.2 5.3 Sel. TBA (mol.%) 68.7 73.6 77.1 74.5 Sel. DTBP (mol.%) 23.3 18.4 11.7 4.5 Composition, wt% IC4= 0.000 0.010 0.038 0.129 1.806 MEOH/MF 0.005 0.022 0.083 0.250 0.384 Acetone 0.013 0.137 0.580 1.182 2.761 TBA 78.494 80.143 86.288 89.745 91.426 DTBP 0.049 0.500 1.692 1.589 0.785 TBHP 20.512 18.119 9.509 4.273 0.241 CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL AND DITERTIARY BUTYL PEROXIDE RUN A 9 10 11 Catalyst .8% Pd on Carbon Catalyst (cc) 100 100 100 Pressure (MPa) 2.1 2.1 2.1 Feed Rate (cc/Hr.) 200 200 200 Temperature (°C) 80 100 120 Time on Stream (Hr) 4 4 4 Space Vel. (cc/cc) 2.0 2.0 2.0 TBHP Conversion (mol.%) 12.0 40.3 96.5 Selectivity IC4= (mol.%) 0.7 1.2 22.1 Sel. Acetone (mol.%) 9.6 10.9 21.7 Sel. Methanol (mol.%) 2.5 3.5 6.5 Sel. TBA (mol.%) 72.3 75.2 73.4 Sel. DTBP (mol.%) 18.1 13.9 5.0 Composition, wt% IC4= 0.000 0.011 0.060 2.721 MEOH/MF 0.005 0.027 0.107 0.465 Acetone 0.013 0.165 0.595 2.778 TBA 78.494 80.216 84.312 89.631 DTBP 0.049 0.410 0.980 0.845 TBHP 20.512 18.051 12.251 0.709

Claims: A method for the decomposition of tertiary butyl hydroperoxide to tertiary butyl alcohol and ditertiary butyl peroxide, wherein a tertiary butyl hydroperoxide charge stock comprising a solution of tertiary butyl hydroperoxide in tertiary butyl alcohol is brought into contact with a hydroperoxide decomposition catalyst, characterized in that the catalyst comprises palladium supported on carbon. A method as claimed in Claim 1, wherein a solution of a tertiary butyl hydroperoxide charge stock in tertiary butyl alcohol that contains from 5 to 30 wt.% of tertiary butyl hydroperoxide is brought into contact with a catalytically effective amount of a hydroperoxide decomposition catalyst in a hydroperoxide decomposition reaction zone in liquid phase under hydroperoxide conversion conditions including a temperature within the range of 20° to 160°C and a pressure of 0.1 to 7 MPa (0 to 1,000 psig) to convert said tertiary butyl hydroperoxide to decomposition products, principally tertiary butyl alcohol and ditertiary butyl peroxide, characterized in that said hydroperoxide decomposition catalyst consists essentially of 0.1 to 1 wt.% of palladium supported on pelleted carbon. A method as claimed in claim 2 wherein the temperature is in the range of 80° to 100°C, the pressure is 0.1 MPa.

Inventors: KNIFTON JOHN FREDERICK, SANDERSON JOHN RONALD, KNIFTON, JOHN FREDERICK, SANDERSON, JOHN RONALD
Applicants: HUNTSMAN SPEC CHEM CORP, HUNTSMAN SPECIALTY CHEMICALS CORPORATION
Application year: 1994
Main classification: C07C29
IPC codes: C07C31, C07C409, C07C27, C07B61, B01J23, C07C29